Compound and coating compositions for adhesion to olefinic substrates

Abstract

The present invention provides an olefin-based block copolymer that has an olefin block that is substantially saturated and at least one (poly)ester or (poly)ether block. The olefin-based block copolymer of the invention can be prepared by reacting a liquid hydroxyl-functional, saturated or substantially saturated olefin polymer with a chain-extension reagent that is reactive with hydroxyl groups and will polymerize in a head-to-tail arrangement of monomer units. The olefin-based block copolymer of the invention can be used to prepare an adhesion promoter that provides excellent adhesion of subsequent coating layers to olefinic substrates like TPO and superior properties as compared to previously used adhesion promoters containing chlorinated polyolefins. Alternatively, the olefin-based copolymers of the invention can be used as an additive in a curable coating composition to provide excellent adhesion to olefinic substrates like TPO, even when used in very minor amounts compared to the amounts required for previously known agents.

What is claimed is:  
     
         1 . An olefin-based block copolymer comprising an olefin block that is substantially saturated and at least one modifying block selected from the group consisting of (polyester blocks and (poly)ether blocks.  
     
     
         2 . An olefin-based block copolymer according to  claim 1 , wherein said block copolymer has at least one functional group selected from hydroxyl groups, carbamate groups, urea groups, carboxylic acid groups, and combinations thereof.  
     
     
         3 . An olefin-based block copolymer according to  claim 1 , wherein said olefin block is derived from a substantially saturated polyhydroxylated polydiene polymer.  
     
     
         4 . An olefin-based block copolymer according to  claim 1 , wherein said olefin block is derived from a hydroxy-functional ethylene/butylene polymer.  
     
     
         5 . An olefin-based block copolymer according to  claim 1 , wherein said olefin-based block copolymer is formed by reacting a hydroxy-functional ethylene/butylene polymer that forms the olefin block with a chain-extension reagent selected from the group consisting of lactones, hydroxy carboxylic acids, alkylene oxides, and combinations thereof, said chain-extension reagent forming the modifying block of the block copolymer.  
     
     
         6 . An olefin-based block copolymer according to  claim 1 , wherein said block copolymer has on average from about 0.7 to about 10 modifying blocks.  
     
     
         7 . An olefin-based block copolymer according to  claim 1 , wherein said block copolymer has on average about 1.8 to about 2 modifying blocks.  
     
     
         8 . An olefin-based block copolymer according to  claim 5 , wherein said dihydroxy ethylene/butylene polymer has a hydroxyl equivalent weight of from about 1000 to about 3000.  
     
     
         9 . An olefin-based block copolymer according to  claim 1 , wherein said block copolymer has a polydispersity of about 1.2 or less.  
     
     
         10 . An olefin-based block copolymer according to  claim 5 , wherein said modifying block has on average from about 0.5 to about 25 monomer units per hydroxyl group of hydroxy-functional ethylene/butylene polymer.  
     
     
         11 . An olefin-based block copolymer according to  claim 5 , wherein said modifying block has on average from about 2 to about 10 monomer units per hydroxyl group of hydroxy-functional ethylene/butylene polymer.  
     
     
         12 . An olefin-based block copolymer according to  claim 5 , wherein said chain-extension reagent includes epsilon-caprolactone.  
     
     
         13 . An olefin-based block copolymer according to  claim 5 , wherein said chain-extension reagent includes ethylene oxide.  
     
     
         14 . An adhesion promoter comprising the olefin-based block copolymer according to  claim 1 .  
     
     
         15 . An adhesion promoter according to  claim 14 , further comprising an organic solvent.  
     
     
         16 . An adhesion promoter according to  claim 14 , further including water and wherein said olefin-based block copolymer has at least one polyethylene oxide segment.  
     
     
         17 . An adhesion promoter according to  claim 14 , further comprising a crosslinker.  
     
     
         18 . An adhesion promoter according to  claim 14 , wherein said block copolymer has at least one functional group selected from hydroxyl groups, carbamate groups, urea groups, and combinations thereof.  
     
     
         19 . An adhesion promoter according to  claim 18 , further comprising a melamine formaldehyde resin.  
     
     
         20 . An adhesion promoter according to  claim 14 , further comprising a conductive carbon black.  
     
     
         21 . A curable coating composition comprising the olefin-based block copolymer according to  claim 1  and at least one film-forming polymer.  
     
     
         22 . A curable coating composition according to  claim 21 , wherein said block copolymer is from about 0.001% to about 4% by weight of the total weight of nonvolatile vehicle.  
     
     
         23 . A curable coating composition according to  claim 21 , wherein said block copolymer is from about 0.1% to about 10% by weight of the total weight of nonvolatile vehicle.  
     
     
         24 . A curable coating composition according to  claim 21 , wherein said film-forming polymer is self-crosslinking and further wherein said olefin-based block copolymer comprises functional groups reactive with said film-forming polymer.  
     
     
         25 . A curable coating composition according to  claim 21 , further comprising a crosslinker reactive with said film-forming polymer and said block copolymer.  
     
     
         26 . A curable coating composition according to  claim 25 , wherein said film-forming polymer is an acrylic polymer, and further wherein each of said acrylic polymer and said block copolymer has at least one functional group selected from hydroxyl groups, carbamate groups, urea groups, and combinations thereof.  
     
     
         27 . A curable coating composition according to  claim 26 , wherein said crosslinker is a melamine formaldehyde resin.  
     
     
         28 . A curable coating composition according to  claim 21 , wherein said curable coating composition is a topcoat composition.  
     
     
         29 . A curable coating composition according to  claim 21 , wherein said curable coating composition is a basecoat composition.  
     
     
         30 . A curable coating composition according to  claim 21 , wherein said curable coating composition is a clearcoat composition.  
     
     
         31 . A curable coating composition according to  claim 21 , wherein said curable coating composition is a primer composition.  
     
     
         32 . A curable coating composition according to  claim 21 , wherein said curable coating composition is a waterborne composition.  
     
     
         33 . A curable coating composition according to  claim 21 , further comprising an organic solvent.  
     
     
         34 . A method of coating an olefin-based substrate, comprising steps of: 
 (a) providing an adhesion promoter according to claim  14 ;    (b) applying the adhesion promoter to an olefin-based substrate;    (c) applying a coating composition over the adhesion promoter; and    (d) heating the substrate having thereon the adhesion promoter and the coating composition to cure the coating composition.    
     
     
         35 . A method according to  claim 34 , wherein the adhesion promoter further comprises a crosslinker.  
     
     
         36 . A method according to  claim 35 , further comprising a step of curing the adhesion promoter before applying the coating composition of step (c).  
     
     
         37 . A method according to  claim 34 , wherein said olefin-based substrate is a thermoplastic polyolefin (TPO).  
     
     
         38 . A method of coating an olefin-based substrate, comprising steps of: 
 (a) providing a curable coating composition according to claim  21 ;    (b) applying the curable coating composition to an olefin-based substrate; and    (c) heating the substrate having thereon the curable coating composition to cure the coating composition.    
     
     
         39 . A method according to  claim 38 , wherein the curable coating composition is a primer composition.  
     
     
         40 . A method according to  claim 38 , wherein the curable coating composition is a topcoat composition.  
     
     
         41 . A method according to  claim 38 , wherein the curable coating composition is a basecoat composition.  
     
     
         42 . A method according to  claim 38 , wherein the curable coating composition is a clearcoat composition and further wherein the olefin-based substrate is a color-in-mold substrate.  
     
     
         43 . A method according to  claim 42 , wherein the olefin-based substrate is a color-in-mold thermoplastic polyolefin (TPO) substrate.  
     
     
         44 . An article comprising an olefin-based substrate coated-according to the method of  claim 34 .  
     
     
         45 . An article comprising an olefin-based substrate coated according to the method of  claim 38 .  
     
     
         46 . An article according to  claim 45 , wherein the curable coating composition is a topcoat composition.  
     
     
         47 . An article according to  claim 45 , wherein the curable coating composition is a basecoat composition.  
     
     
         48 . An article according to  claim 45 , wherein the curable coating composition is a clearcoat composition and further wherein the olefin-based substrate is a color-in-mold substrate.  
     
     
         49 . An article according to  claim 45 , wherein the olefin-based substrate is a color-in-mold thermoplastic polyolefin (TPO) substrate.  
     
     
         50 . An article according to  claim 45 , wherein said article is selected from the group consisting of appliance parts, automotive parts, and automotive trim pieces.